The present invention relates in general to building elements, and, more particularly, to building elements with increased insulating features.
The building industry is expending much effort in the construction of "energy-efficient" units, so-called because features are included in the buildings which are intended to decrease energy transfer between the building and the environment. Such elements as thermal pane windows, extra insulation, seals, and the like have been used to more effectively insulate a building from the environment.
There has also been some effort directed to improving the thermal resistance of structural elements themselves. Such elements as indicated in U.S. Pat. Nos. 823,843 and 1,356,764 have been developed.
Heat transfer occurs via three modes, conduction, convection and radiation. By far, the most efficient mode, for purposes of building insulation, is convection. Thus, any element used in building construction should be designed to maintain this mode of heat transfer to the minimum amount possible.
The elements presently used in the building industry, such as those elements disclosed in the above-referenced patents, which are designed to have better insulating qualities than unmodified elements, have not effectively reduced convection. Thus, the air chambers disclosed in the above-referenced patents extend the full length and/or width of a panel. The air chambers thus do not confine air in all directions, and convection permits heat transfer among the air chambers and within the air chambers thereby vitiating, if not completely destroying, the insulating effect of those air chambers.
Other known devices include a portion of a grid pattern in one ply of a multi-ply material, and another portion of the grid in another ply of that material. The two grid portions generally are oriented perpendicularly with respect to each other. Such grid pattern suffers the above-discussed drawback with regard to insulating quality and reduction via convection, and also is difficult to bond together due to a reduction of surface area.
There is thus a need for a building element having insulating qualities which are improved over an unmodified element and which reduces convection heat transfer through that element.